Corps of Discovery - Was Meriwether Lewis Murdered or Did He Commit
Suicide?

Meriwether
Lewis’s death has been a source of speculation for many years, often
with the mistaken notion that “great men” do not take their
own lives, and that suicide blights the memory of a great life. However,
those closest to Lewis, Thomas Jefferson and William Clark, fully accepted
the reports of suicide. Jefferson reported that Lewis’s family had
a history of what is believed to be manic-depression (bipolar disorder),
and that he had been subject to bouts of deep depression since his youth.

“Governor Lewis had from early life been subject
to hypocondriac [sic] affections. It was a constitutional disposition
in all the nearer branches of the family of his name, it was more immediately
inherited by him from his father...While he lived with me in Washington,
I observed at times sensible depressions of mind, but knowing their
constitutional source, I estimated their course by what I had seen in
the family.”

Clark likewise reported that Lewis had bouts with euphoria and depression
prior to his death, had become deeply in debt, drank heavily and possibly
used opium–all symptoms of bipolar disorder. When Lewis’s
integrity was questioned over billing as a result of his time as Governor
of Louisiana, he left St. Louis deeply troubled and attempted suicide
on the boat ride south. A few days later, October 9, 1809, at a small
inn on the Natchez Trace southwest of Nashville, Lewis apparently shot
himself in despair.

It should be noted, however, that there is the possibility that Lewis
suffered from malaria, a disease that is known, in its later stages, to
cause forms of dementia and erratic behavior. Whether from depression
or malaria, Lewis’s death at so young an age was a tragedy of the
first order. It also caused him to be relatively forgotten by the public
at large until the end of the 19th century, when historians and the public
again looked at the remarkable achievements of the Corps of Discovery,
its Captains, and especially Meriwether Lewis himself.